US9699538B2 - MEMS microphone device - Google Patents
MEMS microphone device Download PDFInfo
- Publication number
- US9699538B2 US9699538B2 US14/832,735 US201514832735A US9699538B2 US 9699538 B2 US9699538 B2 US 9699538B2 US 201514832735 A US201514832735 A US 201514832735A US 9699538 B2 US9699538 B2 US 9699538B2
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- US
- United States
- Prior art keywords
- circuit board
- metal shielding
- electromagnetic shielding
- microphone device
- shielding cover
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
- H04R1/04—Structural association of microphone with electric circuitry therefor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/151—Die mounting substrate
- H01L2924/1515—Shape
- H01L2924/15151—Shape the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/161—Cap
- H01L2924/1615—Shape
- H01L2924/16152—Cap comprising a cavity for hosting the device, e.g. U-shaped cap
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/003—Mems transducers or their use
Definitions
- the present disclosure generally relates to microphone technologies, and more particular, to a micro-electro-mechanical system (MEMS) microphone device with a high electromagnetic shielding performance.
- MEMS micro-electro-mechanical system
- Microphones are applied in various electronic products for converting sound into electrical signals. Compared with other types of microphones, a MEMS microphone is widely used by virtue of some advantages such as small size and low weight. However, because a MEMS microphone needs to receive sound in the air, the MEMS speaker device is apt to suffer electromagnetic interference of environmental electromagnetic waves. This may decrease sound reception quality of the MEMS speaker device.
- FIG. 1 is a schematic, cross-sectional view of a MEMS microphone device according to a first embodiment of the present disclosure.
- FIG. 2 is a schematic, cross-sectional view of a MEMS microphone device according to a second embodiment of the present disclosure.
- FIG. 3 is a schematic, cross-sectional view of a MEMS microphone device according to a third embodiment of the present disclosure.
- FIG. 1 illustrates a MEMS microphone device 100 according to a first embodiment of the present disclosure.
- the MEMS microphone device 100 is applicable to an electronic apparatus such as a smart phone, a tablet computer, or the like.
- the MEMS microphone device 100 includes a circuit board 101 , an electromagnetic shielding cover 102 , and electronic components including a MEMS chip 103 and an application specific integrated circuit (ASIC) chip 104 .
- ASIC application specific integrated circuit
- the electromagnetic shielding cover 102 is mounted on a main surface of the circuit board 101 and cooperates with the circuit board 101 to form an accommodating space.
- the MEMS chip 103 and the ASIC chip 104 are both received in the accommodating space, and are electrically connected to the circuit board 101 .
- the electromagnetic shielding cover 102 includes a main frame 105 and a cover plate 106 .
- the main frame 105 includes a plurality of sidewalls, which are connected in an end-to-end manner and thereby defining a top opening and a bottom opening.
- the cover plate 106 is fixed on the main frame 105 and covers the top opening of the main frame 105 ; and the bottom opening of the main frame 105 is covered by the circuit board 101 when the electromagnetic shielding cover 102 is mounted on the circuit board 101 .
- a surface of the electromagnetic shielding cover 102 which faces the accommodating space, is defined as an inner surface, while an opposite surface of the electromagnetic shielding cover 102 , which is far away from the accommodating space, is defined as an outer surface.
- a metal shielding layer 108 is coated on the inner surface of the electromagnetic shielding cover 102 , the metal shielding layer 108 is adapted for shielding the electronic components (including the MEMS chip 103 and the ASIC chip 104 ) within the accommodating space, and thus prevent these internal electronic components from suffering electromagnetic interference of surrounding electromagnetic waves.
- the metal shielding layer 108 may be coated on the outer surface of the electromagnetic shielding cover 102 ; in yet another embodiment, both the inner surface and the outer surface of the electromagnetic shielding cover 102 may be coated with metal shielding layer 108 respectively.
- the MEMS microphone 100 may further includes a metal shielding shell 107 in the accommodating space, the metal shielding shell 107 is disposed between the electronic components (including the MEMS chip 103 and the ASIC chip 104 ) of the MEMS microphone 100 and the electromagnetic shielding cover 102 , and covers the electronic components.
- the metal shielding shell 107 is adapted for providing additional electromagnetic shielding protection for the MEMS chip 103 and the ASIC chip 104 .
- the metal shielding shell 107 is separate from the electromagnetic shielding cover 102 , and thus a gap is formed between the inner surface of the electromagnetic shielding cover 102 and the metal shielding shell 107 .
- the metal shielding shell 107 may alternatively be attached to the inner surface of the electromagnetic shielding cover 102 .
- the metal shielding shell 107 may be partly attached to the inner surface of the electromagnetic shielding cover 102 by multiple contact points, one or more contact line, or other contact pattern; in another embodiment, the metal shielding shell 107 may be fully attached to the inner surface of the electromagnetic shielding cover 102 .
- the attachment between the metal shielding shell 107 and the inner surface of the electromagnetic shielding cover 102 may be realized by using conductive material, nonconductive material, glue material or other mechanical or physical connection.
- the metal shielding shell 107 and the electromagnetic shielding cover 102 is electrically connected to the circuit board 101 .
- the metal shielding layer 108 of the electromagnetic shielding cover 102 is electrically connected to the circuit board 101 , while the metal shielding shell 107 is insulated from the circuit board 101 , in other words, no electrical connection exists between the metal shielding shell 107 and the circuit board 101 .
- the metal shielding shell 107 may be electrically connected to the circuit board 101 , and in this circumstance, the electromagnetic shielding cover 102 may either be insulated from the circuit board 101 or electrically connected to the circuit board 101 .
- FIG. 2 illustrates a MEMS microphone device 200 according to a second embodiment of the present disclosure.
- the MEMS microphone device 200 is similar to the above-described MEMS microphone device 100 as illustrated in FIG. 1 , but mainly differs in that the metal shielding shell 107 is replaced by another metal shielding layer 207 .
- the MEMS microphone device 200 includes a circuit board 201 , an electromagnetic shielding cover 202 mounted on the circuit board 201 to form an accommodating space, a MEMS chip 203 and an ASIC chip 204 received in the accommodating space and electrically connected to the circuit board 201 .
- the electromagnetic shielding cover 202 includes a main frame 205 and a cover plate 206 covering the main frame 205 .
- An inner surface of the electromagnetic shielding cover 202 is coated with a first metal shielding layer 208 , and a second metal shielding layer 207 is further coated on the first metal shielding layer 208 .
- Material of the second metal shielding layer 207 is different from that of the first metal shielding layer 208 , so that the second metal shielding layer 207 can provide additional electromagnetic shielding protection for the MEMS chip 203 and the ASIC chip 204 .
- first metal shielding layer 208 and the second metal shielding layer 207 is electrically connected to the circuit board 201 , for example, in the present embodiment, the first metal shielding layer 208 is electrically connected to the circuit board 201 while the second metal shielding layer 208 is not electrically connected to the circuit board 201 .
- FIG. 3 illustrates a MEMS microphone device 300 according to a second embodiment of the present disclosure.
- the MEMS microphone device 300 is similar to the above-described MEMS microphone device 200 as illustrated in FIG. 2 , but mainly differs in that a first metal shielding layer 307 and the second metal shielding layer 308 are respectively coated on two opposite surface of an electromagnetic shielding cover 302 of the MEMS microphone device 300 .
- the MEMS microphone device 300 includes a circuit board 301 , an electromagnetic shielding cover 302 mounted on the circuit board 301 to form an accommodating space, a MEMS chip 303 and an ASIC chip 304 received in the accommodating space and electrically connected to the circuit board 301 .
- the electromagnetic shielding cover 302 includes a main frame 305 and a cover plate 306 covering the main frame 305 .
- the first metal shielding layer 307 is coated on an outer surface of the electromagnetic shielding cover 302
- the second metal shielding layer 308 is coated on an inner surface of the electromagnetic shielding cover 302 . Since the second metal shielding layer 308 are not formed on the first metal shielding layer 307 , in the present embodiment, material of the first metal shielding layer 307 can be either the same as that of the second metal shielding layer 308 or different that of the second metal shielding layer 308 .
- first metal shielding layer 307 and the second metal shielding layer 308 is electrically connected to the circuit board 301 , for example, in the present embodiment, the first metal shielding layer 307 is electrically connected to the circuit board 301 while the second metal shielding layer 308 is not electrically connected to the circuit board 301 .
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
- Micromachines (AREA)
Abstract
Description
Claims (7)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201520042995.8U CN204408625U (en) | 2015-01-21 | 2015-01-21 | Mems microphone |
CN201520042995.8 | 2015-01-21 | ||
CN201520042995U | 2015-01-21 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20160212517A1 US20160212517A1 (en) | 2016-07-21 |
US9699538B2 true US9699538B2 (en) | 2017-07-04 |
Family
ID=53432453
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/832,735 Active US9699538B2 (en) | 2015-01-21 | 2015-08-21 | MEMS microphone device |
Country Status (2)
Country | Link |
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US (1) | US9699538B2 (en) |
CN (1) | CN204408625U (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN204465862U (en) * | 2015-01-23 | 2015-07-08 | 瑞声声学科技(深圳)有限公司 | The encapsulating structure of micro-electro-mechanical microphone |
CN106304817B (en) * | 2015-06-04 | 2019-01-18 | 宏碁股份有限公司 | Electronic device |
CN105246314B (en) * | 2015-10-14 | 2018-09-04 | 小米科技有限责任公司 | Shielding case, pcb board and terminal device |
US20190297758A1 (en) * | 2018-03-23 | 2019-09-26 | Intel IP Corporation | Electromagnetic shielding cap, an electrical system and a method for forming an electromagnetic shielding cap |
CN210641072U (en) * | 2019-10-28 | 2020-05-29 | 歌尔科技有限公司 | Sensor packaging structure and electronic equipment |
CN110783318B (en) * | 2019-10-28 | 2022-09-16 | 潍坊歌尔微电子有限公司 | Sensor packaging structure and electronic equipment |
CN110691311A (en) * | 2019-10-28 | 2020-01-14 | 歌尔股份有限公司 | Sensor packaging structure and electronic equipment |
CN212324360U (en) * | 2020-06-30 | 2021-01-08 | 瑞声声学科技(深圳)有限公司 | Microphone (CN) |
CN114125114B (en) * | 2021-11-01 | 2024-05-14 | 维沃移动通信有限公司 | Acoustic module and electronic equipment |
CN114628368B (en) * | 2022-03-10 | 2022-11-11 | 深圳市赛元微电子股份有限公司 | Electromagnetic shielding device of chip circuit module |
Citations (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070158826A1 (en) * | 2005-12-27 | 2007-07-12 | Yamaha Corporation | Semiconductor device |
US20080283290A1 (en) * | 2006-04-28 | 2008-11-20 | Nitto Denko Corporation | Article including sheet-like electromagnetic shielding structure |
US20090207976A1 (en) * | 2005-06-17 | 2009-08-20 | Tomoaki Ito | Portable Container and Protection Film for Preventing Leakage of Information |
US20100038733A1 (en) * | 2008-08-14 | 2010-02-18 | Knowles Electronics, Llc | Microelectromichanical system package with strain relief bridge |
US20100284553A1 (en) * | 2009-05-11 | 2010-11-11 | Stmicroelectronics S.R.L. | Assembly of a capacitive acoustic transducer of the microelectromechanical type and package thereof |
US7868402B2 (en) * | 2007-05-15 | 2011-01-11 | Industrial Technology Research Institute | Package and packaging assembly of microelectromechanical system microphone |
US20120237073A1 (en) * | 2011-03-18 | 2012-09-20 | Analog Devices, Inc. | Packages and methods for packaging mems microphone devices |
US20130177180A1 (en) * | 2012-01-11 | 2013-07-11 | Analog Devices, Inc. | MEMS Microphone with Springs and Interior Support |
US20140017843A1 (en) * | 2010-06-01 | 2014-01-16 | Amkor Technology, Inc. | Semiconductor package and manufacturing method thereof |
US20140050338A1 (en) * | 2011-02-23 | 2014-02-20 | Omron Corporation | Acoustic sensor and microphone |
US20140072151A1 (en) * | 2012-09-10 | 2014-03-13 | Robert Bosch Gmbh | Mems microphone package with molded interconnect device |
US8726496B2 (en) * | 2011-09-22 | 2014-05-20 | Covidien Lp | Technique for remanufacturing a medical sensor |
US8766095B2 (en) * | 2011-12-12 | 2014-07-01 | Unison Industries, Llc | Ignition lead |
US20140191343A1 (en) * | 2011-01-07 | 2014-07-10 | Stmicroelectronics S.R.L. | Sound transducer and microphone using same |
US20150003659A1 (en) * | 2013-06-26 | 2015-01-01 | Infineon Technologies Ag | Electronic device with large back volume for electromechanical transducer |
US20150001648A1 (en) * | 2013-06-27 | 2015-01-01 | Bse Co., Ltd. | Mems microphone |
US8965027B2 (en) * | 2013-02-15 | 2015-02-24 | Invensense, Inc. | Packaged microphone with frame having die mounting concavity |
US20150139467A1 (en) * | 2013-11-21 | 2015-05-21 | Samsung Electro-Mechanics Co., Ltd. | Acoustic device and microphone package including the same |
US20150264464A1 (en) * | 2014-03-14 | 2015-09-17 | Omron Corporation | Capacitance-type transducer |
US9162869B1 (en) * | 2014-07-31 | 2015-10-20 | Merry Electronics (Shenzhen) Co., Ltd. | MEMS microphone package structure having non-planar substrate and method of manufacturing same |
US20150365754A1 (en) * | 2013-01-26 | 2015-12-17 | Audi Ag | Motor vehicle and microphone for a microphone arrangement in the motor vehicle |
US20160037266A1 (en) * | 2013-03-13 | 2016-02-04 | Omron Corporation | Capacitance type sensor, acoustic sensor, and microphone |
US20160044396A1 (en) * | 2014-08-11 | 2016-02-11 | 3R Semiconductor Technology Inc. | Microphone device for reducing noise coupling effect |
US20160052780A1 (en) * | 2014-08-19 | 2016-02-25 | Lingsen Precision Industries, Ltd. | Stacked mems microphone packaging method |
US20160127838A1 (en) * | 2014-10-29 | 2016-05-05 | Robert Bosch Gmbh | Microphone package with molded spacer |
US20160165358A1 (en) * | 2014-12-05 | 2016-06-09 | Industrial Technology Research Institute | Mems microphone package |
US20160167946A1 (en) * | 2013-07-05 | 2016-06-16 | Cirrus Logic International Semiconductor Ltd. | Mems device and process |
US20160192085A1 (en) * | 2014-12-30 | 2016-06-30 | Imagis Co., Ltd. | Mems microphone package using lead frame |
US20160234604A1 (en) * | 2014-10-29 | 2016-08-11 | Akustica, Inc. | Molded Interconnect Mircoelectromechanical System (MEMS) Device Package |
-
2015
- 2015-01-21 CN CN201520042995.8U patent/CN204408625U/en active Active
- 2015-08-21 US US14/832,735 patent/US9699538B2/en active Active
Patent Citations (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090207976A1 (en) * | 2005-06-17 | 2009-08-20 | Tomoaki Ito | Portable Container and Protection Film for Preventing Leakage of Information |
US20070158826A1 (en) * | 2005-12-27 | 2007-07-12 | Yamaha Corporation | Semiconductor device |
US20080283290A1 (en) * | 2006-04-28 | 2008-11-20 | Nitto Denko Corporation | Article including sheet-like electromagnetic shielding structure |
US7868402B2 (en) * | 2007-05-15 | 2011-01-11 | Industrial Technology Research Institute | Package and packaging assembly of microelectromechanical system microphone |
US20100038733A1 (en) * | 2008-08-14 | 2010-02-18 | Knowles Electronics, Llc | Microelectromichanical system package with strain relief bridge |
US20100284553A1 (en) * | 2009-05-11 | 2010-11-11 | Stmicroelectronics S.R.L. | Assembly of a capacitive acoustic transducer of the microelectromechanical type and package thereof |
US20140017843A1 (en) * | 2010-06-01 | 2014-01-16 | Amkor Technology, Inc. | Semiconductor package and manufacturing method thereof |
US20140191343A1 (en) * | 2011-01-07 | 2014-07-10 | Stmicroelectronics S.R.L. | Sound transducer and microphone using same |
US20140050338A1 (en) * | 2011-02-23 | 2014-02-20 | Omron Corporation | Acoustic sensor and microphone |
US20120237073A1 (en) * | 2011-03-18 | 2012-09-20 | Analog Devices, Inc. | Packages and methods for packaging mems microphone devices |
US8726496B2 (en) * | 2011-09-22 | 2014-05-20 | Covidien Lp | Technique for remanufacturing a medical sensor |
US8766095B2 (en) * | 2011-12-12 | 2014-07-01 | Unison Industries, Llc | Ignition lead |
US20130177180A1 (en) * | 2012-01-11 | 2013-07-11 | Analog Devices, Inc. | MEMS Microphone with Springs and Interior Support |
US20140072151A1 (en) * | 2012-09-10 | 2014-03-13 | Robert Bosch Gmbh | Mems microphone package with molded interconnect device |
US20150365754A1 (en) * | 2013-01-26 | 2015-12-17 | Audi Ag | Motor vehicle and microphone for a microphone arrangement in the motor vehicle |
US8965027B2 (en) * | 2013-02-15 | 2015-02-24 | Invensense, Inc. | Packaged microphone with frame having die mounting concavity |
US20160037266A1 (en) * | 2013-03-13 | 2016-02-04 | Omron Corporation | Capacitance type sensor, acoustic sensor, and microphone |
US20150003659A1 (en) * | 2013-06-26 | 2015-01-01 | Infineon Technologies Ag | Electronic device with large back volume for electromechanical transducer |
US20150001648A1 (en) * | 2013-06-27 | 2015-01-01 | Bse Co., Ltd. | Mems microphone |
US20160167946A1 (en) * | 2013-07-05 | 2016-06-16 | Cirrus Logic International Semiconductor Ltd. | Mems device and process |
US20150139467A1 (en) * | 2013-11-21 | 2015-05-21 | Samsung Electro-Mechanics Co., Ltd. | Acoustic device and microphone package including the same |
US20150264464A1 (en) * | 2014-03-14 | 2015-09-17 | Omron Corporation | Capacitance-type transducer |
US9162869B1 (en) * | 2014-07-31 | 2015-10-20 | Merry Electronics (Shenzhen) Co., Ltd. | MEMS microphone package structure having non-planar substrate and method of manufacturing same |
US20160044396A1 (en) * | 2014-08-11 | 2016-02-11 | 3R Semiconductor Technology Inc. | Microphone device for reducing noise coupling effect |
US20160052780A1 (en) * | 2014-08-19 | 2016-02-25 | Lingsen Precision Industries, Ltd. | Stacked mems microphone packaging method |
US20160127838A1 (en) * | 2014-10-29 | 2016-05-05 | Robert Bosch Gmbh | Microphone package with molded spacer |
US20160234604A1 (en) * | 2014-10-29 | 2016-08-11 | Akustica, Inc. | Molded Interconnect Mircoelectromechanical System (MEMS) Device Package |
US20160165358A1 (en) * | 2014-12-05 | 2016-06-09 | Industrial Technology Research Institute | Mems microphone package |
US20160192085A1 (en) * | 2014-12-30 | 2016-06-30 | Imagis Co., Ltd. | Mems microphone package using lead frame |
Also Published As
Publication number | Publication date |
---|---|
US20160212517A1 (en) | 2016-07-21 |
CN204408625U (en) | 2015-06-17 |
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